Thread-passing devices of shuttleless looms

ABSTRACT

A WEFT-THREAD-PASSING DEVICE FOR A SHUTTLELESS LOOM IN WHICH A CLAMP FOR CATCHING THE WEFT THREAD HAS TWO JAWS ADAPTED TO CATCH THE THREAD BY A CLAMPING ACTION ONLY. THE CLAMP JAWS ARE MOUNTED SO THAT THEY CAN MOVE APART TEMPORARILY FROM ONE ANOTHER WHEN THE CLAMP IS IN THE REST POSITION AT THE END OF A RETURN PASS OF WEFT-THREAD-DELIVERY MEANS, WITH THE MOVEMENT APART OF THE JAWS BEING CONTROLLED AND A BLOWER DEVICE BEING PROVIDED TO BLOW A STREAM OF AIR ONTO THE CLAMP WHEN THE WEFT-THREAD-DELIVERY MEANS IS IN ITS REST POSITION.

United States Patent [72] Inventors Yves Juillard;

Bernard Geiger, Mulliouse. Haut-Rhin,

, France [21] Appl. No. 802,119

[22] Filed Feb. 25, 1969 [45] Patented June 28, 1971 [73] Assignee Societe Alsacienne De Constructions Mecaniques De Mulbouse Mulllouse, France [32] Priority Feb. 27, 1968 [33] France [54] THREAD-PASSING DEVICES 0F SHUTTLELESS [51] lnt.Cl ..D03d47/14 [50] Field 01 Search 139/122- -l27, 12, ll, 1

[56] References Cited UNITED STATES PATENTS 2,871,888 2/1959 McDowell 139/122 3,390,707 7/1968 Scherillo 139/122 Primary Examiner-Henry S. Jaudon Attorney-Holman & Stern ABSTRACT: A weft-thread-passing device for a shuttleless loom in which a clamp for catching the weft thread has two jaws adapted to catch the thread by a clamping action only. The clamp jaws are mounted so that they can move apart tem porarily from one another when the clamp is in the rest position at the end of a return pass of weft-thread-delivery means, with the movement apart of the jaws being controlled and a blower device being provided to blow a stream of air onto the clamp when the weft-thread-delivery means is in its rest position.

THREAD-PASSING DEVICES F SIIUTTLELESS LOOMS BACKGROUND OF THE INVENTION The present invention relates to thread-passing devices of shuttleless looms, and, more particularly" to such devices which are designed to clean themselves automatically on each pass.

It is known that, in shuttleless looms, needle-looms or. ribbon-looms in which the weft is drawn, the drawing needle is generally not exposed to a risk of becoming clogged, as it is cleaned by the thread itself whenthe needle opens, but it is also known that the same does not apply to the delivery needle, because the admission of the thread to the vicinity of the clamp in which it is gripped, and its departure from this vicinity at the moment of the transfer of the thread in the middle of the shed, are effected on thesame side relative to the gripping point, so that there is a risk of the gradual formation of a deposit of thread waste capable. of obstructing the efficient catching of the weft.

In order to remedy this drawback, it has already been proposed that several clamping zones be provided on the delivery clamp so that, in the long run an automatic cleaning of the clamp results, the principle being the creation of several clamping zones so that cleaningof one zone has time to be effected during several cycles, with other zones remaining effective during this period.

While this procedure is generally satisfactorywhen there is involved one weft thread which is capable of forming in the clamp a deposit substantially more or less constant in thickness and generally a function of the count and quality of the weft thread, this no longer applies when any kind of mixture of dissimilar weft threads is involved..ln this case, there is the chance that a thick deposit temporarily left by a bulky weft thread may hinder the catching of the next weft thread if the latter is fine and slippery, for example.

So-called "controlled" clamps have also been proposed i.e. those designed-in such a way that the thread is caught by a preliminary opening of the clamp, whichcloses again afterwards on the thread, for example, on the departure of the needie, but such devices also have their drawbacks. In fact, there is a risk of damaging delicate weft threads at the moment of catching, because the clamping force must be sufficiently high to sufi'ice in the case of heavy and strong weft threads. Moreover, during the transfer, it is necessary to control the opening of such clamps for a very short time, and there is a risk, on opening and before closing the drawing clamp, of seeing theweft thread. going back behind because of its inherent elasticity, and, in effect, of the transfer not taking place.

The object of the invention is to providev a thread-passing device which does not have the aforesaid drawbacks of known devices.

SUMMARY OF THE INVENTION The principle underlying the device according to the invention consists in cleaning the delivery needle-while it is in its rest position, during each cycle, before catching a thread and inserting it into the shed. 1

According tothe invention, a weft-thread-passing device for a shuttleless loom comprises a clamp for catchingthe weft thread and having two jawsadapted to catch the thread by clamping action-only, and mounted so as to be able to move apart temporarily from one-another, control means for moving said jaws, apart when said clamp is in the rest position at the end of a return. pass of. weft-thread-delivery means, and a blower device adapted to blow a jet of air on to the clamp when the weft-thread-deliverymeans is in its rest position. Due to this particular conception, the clamp is always clean at the moment of catching the weft thread, so that the risks of failure are reduced to a minimum.

In an advantageous construction, the blower deviceis carried by the batten and comprises a spring-loaded control unit with alternating movement and adapted to strike at the end'of each return stroke of the batten, against a fixed stop mounted on the frame of the loomLThere is thus effected a violent projection of air on the clamp while both its jaws are open, bringing about certain clearance of any waste which may have lodged in between the jaws;

In a particular embodiment, the clamp comprises a fixed jaw integral with the weft-thread-delivery means, and a movable jaw which'is articulatedon the fixed jaw and which has an extension adapted to be pushed back by a fixed cam on the batten to a position such that it opens the clamp and keeps it open when the weft-thread delivery means is at the end of its return pass-and in the rest position. v

The invention will be better understood on reading the following description, and on examining the annexed drawings which show, by way of example, an embodiment of an improved weft-thread-passing device according to the invention.

BRIEF DESCRIPTION OF THE DRAWING FIG. I shows an elevation of a supply clamp for the weft thread in its maximum return position on a weft-shooting weaving frame or loom of the type described in U.S. Pat. No. 3,159,l86:

FIG. 2 is a corresponding plan view: and

FIG. 3 is a partial section along line III III of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION The clamp for catching the weft thread, designated as a unit at I, is mounted at the free end of a delivery needle 2 of the type described in the above-mentioned US. patent. FIG. 1 is a partial view of the upper partof a batten 3, reel 4, a bobbin or' pin 5 continuously supplying weft thread, two thread-guides 6, 7 and a weft-cutting and -holding device indicated as a unit at 9, and described in detail in'U.S. Pat. No. 3,l57,208.

The clamp 1 comprises a fixed jaw 12 integral with needle 2, and a movable jaw 14 which can move away from and towards the fixed jaw I2, such as for example by pivoting around a vertical axis 15, as shown. In this example, the axis 15 is constituted by a stationary screw, and the movable jaw 14 is urged against the fixed jaw 12 by a small spiral compression spring 17 located in a hole 18 in the needle 2, with one end of the spring being supported against an extension I9 of the movable jaw 14, and its other end resting against a plug 21 screwed into the outer end of the hole 18.

The spring 17 is strong enough to prevent the jaws I4 and I2 from moving apart under the pressure of the thread which is clamped therebetween because of the effect of their appropriate configurations on the occasions-of thread passage. The thread is caught by the clamp only because of its being clamped between the two jaws; the latter may, for example, by provided with corrugations such as those shown at 23 and 24 in FIG. 3, of conjugate profile.

When the needle 2 is in its fully withdrawn position, i.e. in its rest position while the batten itself isat its rear dead point, the movable jaw 14 is kept away from the fixed jaw 12 by a cam 27 which is fixed on the batten 3, such as by means of screws 28, and-which'keep back a heel 29 of an extension of the movable jaw 14.

Moreover, there is provided a blower device for the clamp 1 while it is in this position. In'the example, this device is made up of a cylinder 32 which isfix'ed-on the upper side of the batten 3 by means of screws 3 3 orthe like, and in'wh'ich is displaceable a piston 35 equipped with a leather cup-washer 36, v

and integral with an axial sliding stem 37; A spiral compressionspring 41, interposed between the base of the cylinder 32 andthe piston 35, tends to push back the piston constantly, and drive of the piston is effected by the fact that a head 42 at the end of a piston stem 37 strikes against a fixed part 43 of the frame of the machine when'the batten reaches-its-maximum retracted position, i.e. that shown-in the drawings. The part of the cylinder 32 near the base of the cylinder, is fitted with .an air-projecting pipe45"opening just in front of the clamp l when the latter is in its restposition as shown.

The assembly functions as follows: i

When a weft thread has been inserted into the press and the needle -2 finishes its empty return movement, the heel 29 is pushed back by the fixed cam 27, which causes the clamp to open, while at the same time. the head 42 of the stem of the piston of the blower device strikes against the fixed part 43 of the frame of the machine, so that the piston 35 is driven suddenly in opposition to the force of its return spring 41, ensuring that a predetermined quantity of air is projected violently on to the clamp. Any thread waste left between the jaws of the clamp is thus automatically'expelled before the thread-passing device starts out again to catch another weft thread.

It should be noted that the cam 27 has the sole function of opening and keeping open the clamp 1 when the latter is in its maximum retracted position, but, when the clamp sets off for the introduction of a new weft, its heel 29 moves away from the cam 27, and in consequence, the clamp closes again before catching, by a clamping action only, the weft thread 5 presented thereto on its passage. 1

Therefore, there is no question of a clamp which is controlled so as to catch or release the thread, but of a clamp whose weft-thread-catching function is carried out by clamping, with the opening of the clamp being intended only to en sure a wide passage for the jet of air capable of eliminating any thread waste which might have remained in the clamp after the exchange of the weft thread.

Naturally, the invention is not limited to the embodiment described and illustrated, which has been given by way of example; numerous modifications can be made, depending on the applications envisaged, without however going beyond the scope of the invention.

Thus, for example, one might use an air-projecting device which is completely different in structure, such as for example a simple nozzle connected to a source of compressed air under the control of an electroblast gate controlled synchronously with the return pass of the batten.

We claim:

I. A weft-thread-passing device for a shuttleless loom, comprising a clamp for catching the weft thread, said clamp having two jaws adapted to catch the thread by clamping action only, said jaws being mounted so as to be able to move apart temporarily from one another, means for moving said jaws apart when said clamp is in the rest position at the-end of a return pass of weft-thread-delivery means,v and a blower device adapted to blow a jet of air onto the clamp when the weftthread-delivery means is in its rest position to remove any particles of material remaining between the jaws and capable of preventing the jaws from contacting each other.

2. The weft-thread-passing device according to claim 1, including a reciprocating batten, a frame, the blower device being mounted on the batten and comprising a spring-loaded control unit with alternating movement, and adapted to strike at the end of each return pass of the batten, against a fixed stop mounted on the frame.

3. The weft-thread-passing device according to claim I, including a reciprocating batten, the clamp comprising a fixed jaw integral with the weft-thread-delivery means and a movable jaw articulated on the fixed jaw, said movable jaw having an extension adapted to be pushed back by a fixed cam on the batten'to a position such that it opens the clamp and keeps it open when the weft-thread-delivery means is at the end of its return pass and in the rest position.

4. A shuttleless loom having a rearwardly and forwardly reciprocating batten, shed-defining means, a pair of elongated carriers reciprocable in opposite directions transversely of the shed, and insert and pickup clamps attached respectively to the inner ends of the carrier and cooperable for passing the free end of a weft thread presented to the pickup clamp incident to moving the thread successively by the insert and pickup clamps through the shed during rearward movement of the batten, said insert clamp including a pair of jaws, one of said jaws being movable relative to the other jaw, and resilient means maintaining the jaws in resilient contact with each other, means positioned on the batten o erative to se arate said aws against the action of the resllien means when e insert clamp reaches the end of its rearward movement, and batten control means for producing a blast of pressure air and directing such blast between the separated jaws of the insert clamp to remove any particles of material remaining between the jaws and capable of preventing the jaws from contacting each other. 

